diff options
3 files changed, 62 insertions, 4 deletions
diff --git a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs index a8830b346ae..edd51b521fa 100644 --- a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs +++ b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs @@ -1116,13 +1116,13 @@ fn report_non_exhaustive_match<'p, 'tcx>( if ty.is_ptr_sized_integral() { if ty.inner() == cx.tcx.types.usize { err.note(format!( - "`{ty}` does not have a fixed maximum value, so half-open ranges are necessary to match \ - exhaustively", + "`{ty}` does not have a fixed maximum value, so half-open ranges are \ + necessary to match exhaustively", )); } else if ty.inner() == cx.tcx.types.isize { err.note(format!( - "`{ty}` does not have fixed minimum and maximum values, so half-open ranges are necessary to match \ - exhaustively", + "`{ty}` does not have fixed minimum and maximum values, so half-open \ + ranges are necessary to match exhaustively", )); } } else if ty.inner() == cx.tcx.types.str_ { @@ -1143,6 +1143,27 @@ fn report_non_exhaustive_match<'p, 'tcx>( } } + for &arm in arms { + let arm = &thir.arms[arm]; + if let PatKind::Constant { opt_def: Some(def_id), .. } = arm.pattern.kind { + let const_name = cx.tcx.item_name(def_id); + err.span_label( + arm.pattern.span, + format!( + "this pattern doesn't introduce a new catch-all binding, but rather pattern \ + matches against the value of constant `{const_name}`", + ), + ); + err.span_note(cx.tcx.def_span(def_id), format!("constant `{const_name}` defined here")); + err.span_suggestion_verbose( + arm.pattern.span.shrink_to_hi(), + "if you meant to introduce a binding, use a different name", + "_var".to_string(), + Applicability::MaybeIncorrect, + ); + } + } + // Whether we suggest the actual missing patterns or `_`. let suggest_the_witnesses = witnesses.len() < 4; let suggested_arm = if suggest_the_witnesses { diff --git a/tests/ui/match/intended-binding-pattern-is-const.rs b/tests/ui/match/intended-binding-pattern-is-const.rs new file mode 100644 index 00000000000..95c8119cdb9 --- /dev/null +++ b/tests/ui/match/intended-binding-pattern-is-const.rs @@ -0,0 +1,10 @@ +fn main() { + match 1 { //~ ERROR non-exhaustive patterns + //~^ patterns `i32::MIN..=3_i32` and `5_i32..=i32::MAX` not covered + //~| the matched value is of type `i32` + x => {} //~ this pattern doesn't introduce a new catch-all binding + //~^ HELP ensure that all possible cases are being handled + //~| HELP if you meant to introduce a binding, use a different name + } + const x: i32 = 4; //~ NOTE constant `x` defined here +} diff --git a/tests/ui/match/intended-binding-pattern-is-const.stderr b/tests/ui/match/intended-binding-pattern-is-const.stderr new file mode 100644 index 00000000000..99af1c7a16e --- /dev/null +++ b/tests/ui/match/intended-binding-pattern-is-const.stderr @@ -0,0 +1,27 @@ +error[E0004]: non-exhaustive patterns: `i32::MIN..=3_i32` and `5_i32..=i32::MAX` not covered + --> $DIR/intended-binding-pattern-is-const.rs:2:11 + | +LL | match 1 { + | ^ patterns `i32::MIN..=3_i32` and `5_i32..=i32::MAX` not covered +... +LL | x => {} + | - this pattern doesn't introduce a new catch-all binding, but rather pattern matches against the value of constant `x` + | + = note: the matched value is of type `i32` +note: constant `x` defined here + --> $DIR/intended-binding-pattern-is-const.rs:9:5 + | +LL | const x: i32 = 4; + | ^^^^^^^^^^^^ +help: if you meant to introduce a binding, use a different name + | +LL | x_var => {} + | ++++ +help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms + | +LL | x => {}, i32::MIN..=3_i32 | 5_i32..=i32::MAX => todo!() + | ++++++++++++++++++++++++++++++++++++++++++++++++ + +error: aborting due to 1 previous error + +For more information about this error, try `rustc --explain E0004`. |